Using Google Maps in your Android program

[Hstartech]

Now the most part of Android devices have installed Google Maps Application by default. You can use Google Maps in your application for showing different locations.
Let's create a new Android Project. The application will consist of some buttons that will show different locations using different ways.
The first step is to create the layout of the application:

1. <
   
   RelativeLayout xmlns:
   
   android=
   
   "http://schemas.android.com/apk/res/android"
   
2. xmlns:
   
   tools=
   
   "http://schemas.android.com/tools"
   
3. android:
   
   layout_width=
   
   "match_parent"
   
4. android:
   
   layout_height=
   
   "match_parent"
   
5. tools:
   
   context=
   
   "${relativePackage}.${activityClass}"
   
   >
   
6. 
   
7. <
   
   Button
   
   
   
8. android:
   
   id=
   
   "@+id/London"
   
9. android:
   
   layout_width=
   
   "wrap_content"
   
10. android:
    
    layout_height=
    
    "wrap_content"
    
11. android:
    
    layout_below=
    
    "@+id/Earth"
    
12. android:
    
    layout_centerHorizontal=
    
    "true"
    
13. android:
    
    layout_marginTop=
    
    "42dp"
    
14. android:
    
    text=
    
    "Show London"
    
    />
    
15. 
    
16. <
    
    Button
    
    
    
17. android:
    
    id=
    
    "@+id/Earth"
    
18. android:
    
    layout_width=
    
    "wrap_content"
    
19. android:
    
    layout_height=
    
    "wrap_content"
    
20. android:
    
    layout_alignLeft=
    
    "@+id/London"
    
21. android:
    
    layout_alignParentTop=
    
    "true"
    
22. android:
    
    layout_alignRight=
    
    "@+id/London"
    
23. android:
    
    layout_marginTop=
    
    "24dp"
    
24. android:
    
    text=
    
    "Show Earth"
    
    />
    
25. 
    
26. <
    
    Button
    
    
    
27. android:
    
    id=
    
    "@+id/mc"
    
28. android:
    
    layout_width=
    
    "wrap_content"
    
29. android:
    
    layout_height=
    
    "wrap_content"
    
30. android:
    
    layout_centerHorizontal=
    
    "true"
    
31. android:
    
    layout_centerVertical=
    
    "true"
    
32. android:
    
    text=
    
    "Show New Yourk McDonald's"
    
    />
    
33. 
    
34. </
    
    RelativeLayout>
    

The goal of this program is not to create an application with a excellent User Interface. The main task is to test the possibilities of the using Google Maps in your program to show locations. That's way your layout should look something like this:

Now let's initialize all the buttons in the activity to be able to add click listener to them. First of all add these fields to your Activity class

1. Button
   
   Earth;
   
2. Button
   
   London;
   
3. Button
   
   McDonalds;
   

After this you can initialize the buttons in the onCreate method:

1. Africa =
   
   (
   
   Button
   
   )
   
   findViewById(
   
   R.id
   
   .Africa
   
   )
   
   ;
   
2. London =
   
   (
   
   Button
   
   )
   
   findViewById(
   
   R.id
   
   .London
   
   )
   
   ;
   
3. McDonalds =
   
   (
   
   Button
   
   )
   
   findViewById(
   
   R.id
   
   .mc
   
   )
   
   ;
   

And now we can add the listeners to all of the buttons. The onClickListeners are implemented as the anonymous classes. The first example is to show the Earth continent:

1. Africa.setOnClickListener
   
   (
   
   new
   
   OnClickListener(
   
   )
   
   {
   
2. 
   
3. @Override
   
4. public
   
   void
   
   onClick(
   
   View
   
   v)
   
   {
   
5. String
   
   locationString =
   
   "geo:0,10?z=2"
   
   ;
   
6. Uri locationUri =
   
   Uri.parse
   
   (
   
   locationString)
   
   ;
   
7. Intent googleMap =
   
   new
   
   Intent(
   
   Intent.ACTION_VIEW
   
   , locationUri)
   
   ;
   
8. startActivity(
   
   googleMap)
   
   ;
   
9. }
   
10. 
    
11. }
    
    )
    
    ;
    

Now let's take a look on the location string. It has the following format:

1. geo:
   
   latitude,longitude?
   
   z=
   
   zoom
   

The first two parameters are clear.These are the coordinates of the place what you want show. The last one is the zoom parameter - the maximal value for zoom is 23 and the minimum value is 2.
You can see that there is not always a good idea to use coordinates. Let's show the London by simply specifying the name of the city:

1. London.setOnClickListener
   
   (
   
   new
   
   OnClickListener(
   
   )
   
   {
   
2. 
   
3. @Override
   
4. public
   
   void
   
   onClick(
   
   View
   
   v)
   
   {
   
5. String
   
   locationString =
   
   "geo:0,0?q=London"
   
   ;
   
6. Uri locationUri =
   
   Uri.parse
   
   (
   
   locationString)
   
   ;
   
7. Intent googleMap =
   
   new
   
   Intent(
   
   Intent.ACTION_VIEW
   
   , locationUri)
   
   ;
   
8. startActivity(
   
   googleMap)
   
   ;
   
9. }
   
10. 
    
11. }
    
    )
    
    ;
    

You can see that the format of the location string is now much more clear:

1. geo:
   
   0
   
   ,0
   
   ?
   
   q=
   
   street+
   
   address
   

You can specify any correct street address to be shown.
Also, you can specify a search query for this format. Let's find McDonald's In New York:

1. McDonalds.setOnClickListener
   
   (
   
   new
   
   OnClickListener(
   
   )
   
   {
   
2. 
   
3. @Override
   
4. public
   
   void
   
   onClick(
   
   View
   
   v)
   
   {
   
5. String
   
   locationString =
   
   "geo:0,0?q=New Your McDonald\'
   
   s"
   
   ;
   
6. Uri locationUri =
   
   Uri.parse
   
   (
   
   locationString)
   
   ;
   
7. Intent googleMap =
   
   new
   
   Intent(
   
   Intent.ACTION_VIEW
   
   , locationUri)
   
   ;
   
8. startActivity(
   
   googleMap)
   
   ;
   
9. }
   
10. 
    
11. }
    
    )
    
    ;
    

Now you need some basic things how to show different locations from your application. The Google Maps can be integrated in the Android application without starting the Google Maps application. But it's another theme for another article.

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